When Sustainable Nanochemistry Meets Agriculture: Lignin Nanocapsules for Bioactive Compound Delivery to Plantlets

Abstract

First developed for biomedical and industrial applications, nanovectors have recently been extended to agriculture. Therefore, innovative plant growing procedures making use of nanoparticles should be adapted to sustainable processes and materials. This work aims at proposing newly synthetized polymeric nanocapsules (NCs) to be used as biocompatible vectors for delivery of bioactive compounds to plants. Nanoparticles were fabricated from lignin, which is the main byproduct of wood processing and is currently a waste material. Lignin can thus find a virtuous fate and be reused in the context of circular economy. Specifically, we loaded lignin NCs with Gibberellic Acid (GA), assessing that stable and reproducible nanoparticles could be obtained in a range of GA content that is relevant for delivery purposes, i.e. 0.5-1.5 mg ml-1. Plain and GA-loaded NCs were characterized by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM). Assays of cytotoxicity and cargo release were carried out in two model plants, Eruca vesicaria and Solanum lycopersicum. These experiments, conducted both in vitro and in vivo, included the investigations of the percentage of germination, the stem and primary root lengths, as well as the fresh and dry weight of treated plants vs non-treated ones. Furthermore, NCs were loaded with Fluorol Yellow 088 to track their entrance and accumulation in seeds and seedlings.

Lignin Nanoparticles: A Promising Tool to Improve Maize Physiological, Biochemical, and Chemical Traits

“…Furthermore, it has been hypothesized that lignin could increase seed germination for its capacity to act directly on mitotic activity [ 55 ]. In a recent paper, Falsini et al [ 56 ] postulated beneficial effects on plants due to many hydrophilic groups in the lignin chemical structure. In particular, these groups, located on the external surface of nanoparticles in an aqueous environment, could positively affect the processes related to plant germination and growth by increasing the water availability.…”

Lignin for Bioeconomy: The Present and Future Role of Technical Lignin

“…The lignin-based dispersants, binders, and processing-aids for agricultural applications are among the primary applications of lignosulfonates. These applications in agriculture include seed coating, granulations, wettable powder, and suspension dispersants [166,167]. A few examples are Borresperse CA/NA/3A, Norlig 11D, and Yiltrazine NA from [168] Borregard Lignotech.…”

Multifunctional lignin-based nanocomposites and nanohybrids

“…Lignin-based nanocapsules (LNCs) have been also applied as biocompatible vectors to deliver bioactive compounds, such as gibberellic acid (GA), to modulate the plant-growing process, as proposed by Falsini and co-authors. 439 Cargo release and cytotoxicity assays were carried out in two model plants, Eruca vesicaria and Solanum lycopersicum , using lignin concentrations up to 1% w/v. The different seeds were treated with Ga-loaded LNCs, and the seedlings showed tolerance without symptoms of toxicity.…”